1. Field of the Invention
This invention relates to an external combustion engine apparatus and, more particularly, to a closed cycle, two-fluid, externally cooled, vapor standard engine apparatus and method.
2. The Prior Art
A conventional external combustion engine receives energy from an external combustion source to vaporize a single working fluid. The working fluid is utilized in an expansion engine apparatus where the thermal energy of the working fluid is converted to mechanical energy. In a closed cycle system, the working fluid is condensed after passing through the mechanical expansion engine and returned to the boiler where it is again vaporized. While certain savings are realized by returning the working fluid to the boiler, it is well-known that unless extensive condenser apparatus is provided, a substantial backpressure exists in the working fluid thereby lowering the efficiency of the mechanical expansion engine.
Dual fluid systems are known in the art and generally incorporate a lower boiling point working fluid and a higher boiling point solvent. The solvent is chosen so that it has a relatively high degree of absorptivity for the working fluid. One such system is the well-known ammonia/water system which is used for numerous applications, primarily in the field of refrigeration. However, until the present invention, none of the prior art systems has utilized a closed vapor standard heat engine to convert thermal energy into mechanical energy whereby the working fluid is distilled from a solution consisting of working fluid and solvent and thereafter superheated prior to being passed into the mechanical expansion engine. The exhausted working fluid is absorbed in solvent with the heat of absorption being recovered by an external cooling source.
It, therefore, would be a significant advancement in the art to provide a closed cycle, vapor standard heat engine for converting thermal energy from an external combustion source to mechanical energy utilizing a dual fluid system. It would also be an advancement in the art to provide a dual fluid system whereby a solvent fluid has a high degree of absorptivity for a working fluid and wherein the heat of absorption of the system is recovered through an external cooling source. Such a novel apparatus and method is disclosed and claimed herein.